Present wood chipping installations are exemplified by the disclosure of U.S. Pat. No. 3,069,101 to Wexell, dated Dec. 18, 1962. Such installations include a wood chipping machine having a chipper disc which is driven for rotation on a horizontal axis and carries on one face a plurality of cutter or chipper knives or blades. Pieces of wood to be chipped, such as logs or slabs, edgings or trim ends from a sawmill are fed at an acute angle to the disc, usually on some type of horizontal conveyor into a horizontal infeed chute or spout on the machine. The chipper disc also usually is provided with centrifugal fan blades, and a housing enclosing the disc is provided with a discharge outlet which communicates with a blowpipe that directs the air-entrained chipped material to a separating device. Such separating device usually has a plurality of vibrating screens which separate proper or desired size chips from oversize chips and from fines. Means normally are provided for conveying the oversize chips back to the chipping machine for rechipping.
In an installation of the foregoing type the separating device usually is located at an elevation considerably higher than the top of the chipping machine so that the oversize chips can be conveyed by gravity, i.e. without further elevation, back to the machine. While such installations are satisfactory, improvements are possible and desirable for resulting savings in construction and operation.